Preparation of tetraethoxysilane-based silica aerogels with polyimide cross-linking from 3, 3′, 4, 4′-biphenyltetracarboxylic dianhydride and 4, 4′-oxydianiline

Fei, Zhifang; Yang, Zichun; Chen, Guobing; Li, Kunfeng

doi:10.1007/s10971-017-4566-x

Cited by 23 publications

(16 citation statements)

References 32 publications

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“…[ 31 ] Furthermore, the peak at 1062 cm −1 corresponds to the vibration of SiOSi of silica network. [ 13 ] The absorption bands at 3000–2850 cm −1 and the peak located at 837 cm −1 are attributed to the asymmetric and symmetric CH stretching vibration and the rocking vibration of CH 3 , respectively, indicating the introduction of BTMSPA and methyl‐rich MTMS in the aerogels. [ 33 ] The peaks observed at around 1236 and 782 cm −1 correspond to the deformation and stretching vibration of SiC bond, respectively, indicating that the silica network is cross‐linked with PI.…”

Section: Resultsmentioning

confidence: 99%

“…H1 hysteresis loop can be observed in materials with uniformly distributed spherical particle aggregates or cylindrical mesopores, while H3 hysteresis loop is often reported for flake granular material or slit pore material. [ 13,31 ] Pore structure parameters of the hybrid aerogels are listed in Table 2 and pore size distributions are shown in Figure 5b. With the increase of silica sol volume, the specific surface area decreases from 422.0 to 186.5 m 2 g −1 , while the pore volume decreases from 3.24 to 0.63 cm 3 g −1 .…”

Section: Resultsmentioning

confidence: 99%

“…[ 12 ] First, they are inherently fragile due to the weak linkage of the solid phase particles. [ 13–15 ] Second, the abundant pores in aerogels can easily adsorb moisture in the air, which makes the aerogels moisture sensitive. [ 16–17 ] The extreme fragility and hygroscopic nature of silica aerogels limit their practical applications in various fields.…”

Section: Introductionmentioning

confidence: 99%

“…[ 29 ] In recent years, PI and silica have been combined to prepare PI‐silica hybrid aerogels with improved mechanical properties. [ 13,30,31 ] Nevertheless, the moisture resistance of the hybrid aerogels is often neglected, which is also very important for practical applications.…”

Section: Introductionmentioning

confidence: 99%

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Moisture‐Resistant and Mechanically Strong Polyimide‐Polymethylsilsesquioxane Hybrid Aerogels with Tunable Microstructure

Wang

Liu

et al. 2021

Macro Materials & Eng

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Moisture‐resistant and mechanically strong polyimide (PI)‐polymethylsilsesquioxane hybrid aerogels with doubly cross‐linked structures are synthesized through sol–gel technology and supercritical CO2 fluid drying. By using bis(trimethoxysilylpropyl) amine as a cross‐linker, the end‐capped polyamide acid derived from biphenyl‐3,3′,4,4′‐tetracarboxylic dianhydride and 4,4′‐oxydianiline is cross‐linked with a silica network using methyltrimethoxysilane as the silica source precursor. The resultant hybrid aerogels show low density (0.12–0.15 g cm−3), low thermal conductivity (0.032–0.049 W m−1 K−1), high hydrophobicity (125–140°) and good thermal stability (above 435 °C) with tunable microstructure. With the increase of silica sol volume, the microstructure of hybrid aerogels transforms from fibrous network to hierarchical microstructure. Aerogels with high content of silica sol exhibit good moisture resistance, high Young's modulus (Max. 19.6 MPa), and high specific modulus (Max. 131 kN m kg−1), which are attributed to their unique hierarchical microstructure with a sheet skeleton. These hybrid aerogels are promising in the fields of thermal insulation, aerospace applications and so on.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Moisture‐Resistant and Mechanically Strong Polyimide‐Polymethylsilsesquioxane Hybrid Aerogels with Tunable Microstructure

Wang

Liu

et al. 2021

Macro Materials & Eng

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“…This leads to severe modifications in the transport properties of the polymer, the permeability, and selectivity coefficients growing several times [83,84]. As a consequence, scCO2 is largely used in the production of nanoparticles, foams, aerogels, and membranes based on linear [85][86][87] or cross-linked [88][89][90][91][92] PIs. These materials have interesting features (high porosity, tunable shrinkage, nano-and micro-cavities, high surface area, ultralow dielectric constant, and mechanical resilience) that open up new possibilities in the applicability of PI-based systems such as catalytic systems, separation membranes, aviation, aerospace, construction, and others [93][94][95][96][97].…”

Section: Synthesis and Processing Of Pis In Supercritical Fluidsmentioning

confidence: 99%

New High-Performance Materials: Bio-Based, Eco-Friendly Polyimides

Rusu¹,

Abadie²

2021

Polyimide for Electronic and Electrical Engineering Applications

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The development of high-performance bio-based polyimides (PIs) seems a difficult task due to the incompatibility between petrochemical-derived, aromatic monomers and renewable, natural resources. Moreover, their production usually implies less eco-friendly experimental conditions, especially in terms of solvents and thermal conditions. In this chapter, we touch some of the most significant research endeavors that were devoted in the last decade to engineering naturally derived PI building blocks based on nontoxic, bio-renewable feedstocks. In most cases, the structural motifs of natural products are modified toward amine functionalities that are then used in classical or nonconventional methods for PI synthesis. We follow their evolution as viable alternatives to traditional starting compounds and prove they are able to generate eco-friendly PI materials that retain a combination of high-performance characteristics, or even bring some novel, enhanced features to the field. At the same time, serious progress has been made in the field of nonconventional synthetic and processing options for the development of PI-based materials. Greener experimental conditions such as ionic liquids, supercritical fluids, microwaves, and geothermal techniques represent feasible routes and reduce the negative environmental footprint of PIs' development. We also approach some insights regarding the sustainability, degradation, and recycling of PI-based materials.

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Ultrasound‐assisted freeze‐drying strategy to enhance nanoparticle dispersion in aerogels: A case study on polyimide/silica nanocomposite aerogel

Xiao,

Zhao,

et al. 2023

Polymer Engineering & Sci

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Thermal protection materials should possess light weight, excellent thermal insulation, flame retardant and hydrophobic properties. Aerogel are considered a promising thermal protection material due to its high porosity and low density. Among them, nano‐silica/polyimide composite aerogel has been intensively studied as they can solve the problem of fragility of nano‐silica aerogel while ensuring thermal insulation and flame retardant performance. However, the problems of nanoparticle agglomeration and the tedious preparation process remain unsolved. The ultrasound‐assisted freeze‐drying (UAFD) strategy presented in this paper avoids the tedious silica solution preparation process by hydrolyzing silica precursors to achieve good dispersion of silica. This strategy replaces the traditional approach of functionalized modification of silica nanoparticles to inhibit their agglomeration with a new method of nanoparticle dispersion by ultrasound and rapid freezing to lock the dispersed state. The UAFD strategy enables the rapid and efficient preparation of well‐dispersed nano‐silica/polyimide composite aerogels, and the hierarchical pore structure of the composite aerogels is imparted by this facile preparation strategy that cooperates with the co‐regulation capability of the tert‐butanol on the morphology of the ice template. The aerogels have substantially improved thermal insulation, flame retardant, and hydrophobic properties when compared with those prepared by conventional freeze‐drying methods.Highlights Ultrasound‐assisted freeze‐drying (UAFD) enhances nanoparticles dispersion. UAFD and tert‐butanol synergistically prepared hierarchically pore structure. Thermal protection performance of aerogels prepared by UAFD is improved.

show abstract

Preparation of tetraethoxysilane-based silica aerogels with polyimide cross-linking from 3, 3′, 4, 4′-biphenyltetracarboxylic dianhydride and 4, 4′-oxydianiline

Cited by 23 publications

References 32 publications

Moisture‐Resistant and Mechanically Strong Polyimide‐Polymethylsilsesquioxane Hybrid Aerogels with Tunable Microstructure

Moisture‐Resistant and Mechanically Strong Polyimide‐Polymethylsilsesquioxane Hybrid Aerogels with Tunable Microstructure

New High-Performance Materials: Bio-Based, Eco-Friendly Polyimides

Ultrasound‐assisted freeze‐drying strategy to enhance nanoparticle dispersion in aerogels: A case study on polyimide/silica nanocomposite aerogel

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